A semiconductor device comprises driver circuitry, an analog-digital (AD) converter, and processing circuitry. The driver circuitry is configured to supply a drive signal to a sensor array in a sensing frame comprising 2N bursts, N being an integer of two or more. The mixer circuitry is configured to modulate a plurality of carrier waves with a plurality of sensing signals corresponding to capacitances of a plurality of sensing electrodes of the sensor array, respectively, to output a plurality of mixer outputs. A number of the plurality of sensing electrodes is 2N−1 or 2N. The AD converter is configured to perform AD conversion on a sum signal of the plurality of mixer outputs. The processing circuitry is configured to detect an object based on the output of the AD converter.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A semiconductor device, comprising: driver circuitry configured to supply a drive signal to a sensor array in a sensing frame comprising 2N bursts, N being an integer of two or more; mixer circuitry configured to modulate a plurality of carrier waves with a plurality of sensing signals corresponding to capacitances of a plurality of sensing electrodes of the sensor array, respectively, to output a plurality of mixer outputs, a number of the plurality of sensing electrodes being 2N−1 or 2N; an analog-digital (AD) converter configured to perform AD conversion on a sum signal of the plurality of mixer outputs; and processing circuitry configured to detect an object based on the output of the AD converter, wherein one of a first carrier wave of the plurality of carrier waves and a second carrier wave of the plurality of carrier waves is modulated with one of the plurality of sensing signals during a plurality of first bursts of the 2N bursts, the first carrier wave being in phase with the drive signal, and the second carrier wave having a phase shifted from that of the first carrier wave by π.
2. The semiconductor device, according to claim 1 , wherein two of the plurality of first bursts are not adjacent in a time domain.
3. The semiconductor device, according to claim 1 , wherein the plurality of sensing signals comprises: a first sensing signal associated with a first sensing electrode of the plurality of sensing electrodes; and a second sensing signal associated with a second sensing electrode of the plurality of sensing electrodes; and wherein the first carrier wave or the second carrier wave is modulated with the first sensing signal during a second burst of the 2N bursts, and a third carrier wave of the plurality of carrier waves having a phase different from that of the first and second carrier waves is modulated with the second sensing signal during the second burst.
4. The semiconductor device according to claim 1 , wherein a third carrier wave of the plurality of carrier waves having a phase different from that of the first and second carrier waves is modulated with the one of the plurality of sensing signals during a second burst of the 2N bursts other than the plurality of first bursts.
5. The semiconductor device according to claim 4 , wherein the second burst is disposed between two of the plurality of first bursts in the sensing frame.
6. The semiconductor device according to claim 1 , wherein the processing circuitry is configured to generate a first digital output corresponding to an effective signal component for detecting the object and a second digital output corresponding to a noise component.
7. The semiconductor device according to claim 6 , wherein the mixer circuitry is configured to modulate one of the first carrier wave, the second carrier wave, a third carrier wave of the plurality of carrier waves, and a fourth carrier wave of the plurality of carrier waves with each of the plurality of sensing signals to output the plurality of mixer outputs, the third carrier wave having a phase delayed from that of the first carrier wave, and the fourth carrier wave having a phase advanced from that of the first carrier wave, and wherein the processing circuitry comprises: a digital demodulator configured to demodulate an output of the AD converter with first and second local carriers, the first local carrier being in phase with the drive signal, and the second local carrier having a phase shifted from that of the first local carrier; and a decoder configured to generate the first digital output and the second digital output based on an output of the digital demodulator.
8. The semiconductor device according to claim 1 , wherein the driver circuitry comprises a plurality of drivers configured to supply drive signals to the plurality of sensing electrodes, respectively.
9. A capacitive sensing system, comprising: a sensor array; driver circuitry configured to supply a drive signal to a sensor array in a sensing frame comprising 2N bursts, N being an integer of two or more; mixer circuitry configured to modulate a plurality of carrier waves with a plurality of sensing signals corresponding to capacitances of a plurality of sensing electrodes of the sensor array, respectively, to output a plurality of mixer outputs, a number of the plurality of sensing electrodes being 2N−1 or 2N; an AD converter configured to perform AD conversion on a sum signal of the plurality of mixer outputs; and processing circuitry configured to detect an object based on the output of the AD converter, wherein one of a first carrier wave of the plurality of carrier waves and a second carrier wave of the plurality of carrier waves is modulated with one of the plurality of sensing signals during a plurality of first bursts of the 2N bursts, the first carrier wave being in phase with the drive signal, and the second carrier wave having a phase shifted from that of the first carrier wave by π.
10. The capacitive sensing system according to claim 9 , wherein two of the plurality of first bursts are not adjacent in a time domain.
11. The capacitive sensing system according to claim 9 , wherein the plurality of sensing signals comprises: a first sensing signal of the plurality of sensing signals associated with a first sensing electrode of the plurality of sensing electrodes; and a second sensing signal of the plurality of sensing signals associated with a second sensing electrode of the plurality of sensing electrodes; and wherein the first carrier wave or the second carrier wave is modulated with the first sensing signal during a second burst of the 2N bursts, and a third carrier wave of the plurality of carrier waves having a phase different from that of the first and second carrier waves is modulated with the second sensing signal during the second burst.
12. The capacitive sensing system according to claim 9 , wherein the sensor array is integrated in a display panel.
13. A method, comprising: supplying a drive signal to a sensor array in a sensing frame comprising 2N bursts, N being an integer of two or more; modulating a plurality of carrier waves with a plurality of sensing signals corresponding to capacitances of a plurality of sensing electrodes of the sensor array, respectively, to output a plurality of mixer outputs, a number of the plurality of sensing electrodes being 2N−1 or 2N, performing AD conversion on a sum signal of the plurality of mixer outputs to generate a digital data stream; and detecting an object based on the digital data stream, wherein one of a first carrier wave of the plurality of carrier waves and a second carrier wave of the plurality of carrier waves during a plurality of first bursts of the 2N bursts, the first carrier wave being in phase with the drive signal, and the second carrier wave having a phase shifted from that of the first carrier wave by π.
14. The method according to claim 13 , wherein two of the plurality of first bursts are not adjacent in a time domain.
15. The method according to claim 13 , wherein the plurality of sensing signals comprises: a first sensing signal of the plurality of sensing signals associated with a first sensing electrode of the plurality of sensing electrodes; and a second sensing signal of the plurality of sensing signals associated with a second sensing electrode of the plurality of sensing electrodes; and wherein the first carrier wave or the second carrier wave is modulated with the first sensing signal during a second burst of the 2N bursts, and a third carrier wave of the plurality of carrier waves having a phase different from that of the first and second carrier waves is modulated with the second sensing signal during the second burst.
16. The method according to claim 13 , wherein a carrier wave having a phase different from that of the first and second carrier waves is modulated with the one of the plurality of sensing signals during a second burst of the 2N burst other than the plurality of first bursts.
17. The method according to claim 16 , wherein the second burst is disposed between two of the plurality of first bursts in the sensing frame.
18. The method according to claim 13 , wherein detecting the object comprises: generating a first digital output corresponding to an effective signal component for detecting the object and a second digital output corresponding to a noise component.
19. The method according to claim 18 , wherein generating the plurality of mixer outputs comprises: modulating one of the first carrier wave, the second carrier wave, a third carrier wave of the plurality of carrier waves, and a fourth carrier wave of the plurality of carrier waves with each of the plurality of sensing signals to output the plurality of mixer outputs, the third carrier wave having a phase delayed from that of the first carrier wave, and the fourth carrier wave having a phase advanced from that of the first carrier wave, and wherein generating the first digital output and the second digital output comprises: demodulating the digital data stream with first and second local carriers to generate a demodulated data, the first local carrier being in phase with the drive signal, and the second local carrier having a phase shifted from that of the first local carrier; and generating the first digital output and the second digital output based on the demodulated data.
20. The method according to claim 13 , further comprising: supplying a set of drive signals to the plurality of sensing electrodes, respectively.
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August 6, 2019
October 6, 2020
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